Carton



Dec. 2l, 1943. M. E. HoLY 2,337,198,

CARTON Filed Sept. l5, 1941 2 Sheets-Sheet l f3 5f ff y 9 f:

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,Z3/; T" A .9 9 in f E? E 32 E 25 Dec. 21, 1943. M, How 2,337,198

CARTON Filed Sept. 15, 1941 2 Sheets-Sheet 2 Patented Dec. 21, 1943CARTON Mitchel E. Holy, Philadelphia, Pa., assignor to ContainerCorporation of America, Chicago, Ill., a corporation of DelawareApplication september 15.1941, serial No. 410,797

(ci. 22H9) 3Claims.

This invention pertains to cartons or contain; ers composed ofpaperboard, berboard and the like and, more particularly, -to so-calledselflccking or snap-lock end closures for such articles wherein theclosure ilaps are so constructed and arranged as to cause substantiallyautomatic interengagement or interlocking of the end ilaps when they areinfolded slightly beyond their intended nal relationship to one another;

One of the primary objects f the invention is to provide a self-lockingor snap-lock end closure of such construction as to afford ease andspeed of manipulation in eifecting closure of the carton end, the whileproviding a strong and relatively rigid carton end rmly resistant toforces tending to cause accidental opening.'

Another important object is to provide an inexpensive and simplesnap-lock nap construction whereby all four of the naps at one end of afourwalled carton may be interlocked with rapidity and sureness by easymanipulation. In this connection it should be stated that self-lockingof four flaps of a carton end closure is not broadly new but priorstructures of this sort are either complicated or expensive orinefficient or ineffective or otherwise unsatisfactory, the presentinvention avoiding all such defects of the prior art.

Still another important object is to provide a self-locking or snap-lockarrangement whereby all of the several locking iiaps may be interengagedsimultaneously by a simple and practically single finger manipulationafter the several interlocking flaps have been folded over the cartonend in their proper order.

Many other objects and the advantages of the invention will beappreciated and understood, and numerous' uses will become apparent asthe description and claims are read in conjunction with the drawings, inwhich:

Fig. 1 illustrates a certain blank, both ends of which embody theself-locking iiaps constituting a preferred form of the invention;

Fig. 2 is a perspective view of a carton formed from a blank such asthat of Fig. 1 showing the rst closing operation with one pair of endclosure ilaps folded inwardly over the carton end;

Fig. 3 is a View similar to that of Fig. 2 showing the second flapfolding operation in process of being performed to effect the iirstlock;

Fig. 4 is a view similar to that of Fig. 2 showing the iinal flapfolding operation to effect the iinal lock with the fourth flap; and

Fig. 5 is an end view of the carton with the though it is hereinillustrated and described as applied to a. parallelepiped shape ofiiberboard receptacle in which both ends embody the closure means of apreferred form of the invention. Obviously either end alone might be soequipped and the other end otherwise closed. A sheet of suitablematerial such as iiberboard is cut and scored in proper dimensions toprovide the blank of Figure l including what willY be termed, forconvenient reference, side panels 1 and 9, front and back panels 8 andI0, respectively, a securing strip II, and, at eachend, a series ofinterlocking closure naps designated I2, I3 and I4. Since the endclosure flaps at one end are similar in shape, construction and functionto those of the opposite end, a. description of one series shouldsuiiice for both.

Score lines I5, I6, Il, I8, I9 and 2l segregate the several panels andclosure aps from one another and permit, iirst, the panels to be foldedinto tubular body form with the adhesive carrying securing strip I Isecured to the inner or outer face of side panel .l (depending on thedirection of folding), and, second, the end closure naps to be folded atrightangles tothe side, back and front panels over the carton end andthere interlocked with one another. Each of closure naps I2, at one endof the carton, has a kerf or slit, one part 22 of which intersects andextends from that free side edge of the iiap I2 which is adjacent to thefront nap I3, to a, point, say onethird to two-fths of the width of theap and there connects with a part 23 extending substantially at rightangles to the first part and terminating a substantial distance short ofthe outer free edge of the nap. The two parts of each slit are joined,preferably by a fillet to avoid tearing of the liap and together providea depressible tabblike part 24 normally occupying the plane of` the iiapbut susceptible of being deected out of that plane momentarily duringthe locking operation to be described.

The inner portions 25 of the free side edges of rear closure ilap I4converge outwardly and the outer portions are formed into what may betermed side or lateral locking tabs 26. The nap I4 is also provided witha U-shaped slit 21 disposed with the legs of the U directed toward thefree outer edge 28 and the base of the U parallel or substantiallyparallel to the said free outer edge. The portion of flap I4 which isconfined between the legs and base of the U-shaped slit, of course,normally occupies the plane oi the nap but, like the tab-like parts 24defined by the slits 22-23, is susceptibleof being deflected out of suchplane during certain locking operations hereinafter related. The flap I6preferably is of a width, from score line 2| to its outer free edge 28,substantially equal to the width of the carton from front to rear'whenset-up, i. e. equal to the width of the side wall panel 1 or 9, and thelocking tabs 26 are so positioned withl respect to the slits 22-23`thatthe aps I2 and I4 may be interlocked with one another as will appear.

The front closure ap I3 preferably has arcuately converging free sideedges 29 which terminate at a locking tab 3|v which, in turn, terminatesthe flap I3 and is designed to be passed through the slit 21 to effectinterlocking of the ilaps I3 and |4. The width of flap I3, from the freeterminal edge 32 of tab 3| to scoreline 2|, preferably is somewhat lessthan the perpendicular distance between the front and rear panels of thecarton but in any event this flap I3 is proportioned suitably to t andinterlock with the flap I4 as will be appreciated.

When the carton has been set-up into tubular form and its `end is to beclosed the first operation is to fold the side ilaps I2 inwardly overthe end of the package. Thereafter operations may progress in either oftwo ways, namely, the rear flap and front flap may be folded over theend and in the order mentioned, each being caused to lock with theunderlying ilap or aps in succession or, the rear and then the front napmay be folded down over the end and the interlocking between the rearflap and the side aps and between the front ap and the rear flapeffected simultaneously. In performing the locking operations by thesuccessive method the rear ap I4 is folded down over and against theside flaps I2, whereupon pressure of the lingers of the operator appliedalong the center portion of the outer free edge 28 and in a directiontending to push `the aps into the tubular body of the carton, will causethe tabs 26 to depress these portions 24 which are bounded by the slits22- 23 to positions out of the planes of the side aps and to positionswhere the outer ends of tabs 26 will pass through the slit parts 22.This operation is illustrated in Figure 3. Release of the fingerpressure permits the natural resilience of the carton material to returnthe side and rear flaps to their normal flat positions across and squarewith the carton end, the three flaps being securely locked together.

A similar method of procedure serves to interlock the front and rearflaps. In this operation the front flap I3 is folded over and downagainst the outer surface of rear ap I4 and the operator presses againstthe outer surface of the front flap between the tab 3| and scoreline 2|(or I9 as the case may be) to bow the entire assembly of end apsinwardly of the carton body as is .illustrated in Figure 4. During thisdepressing or bowing of the aps the pressure of tab 3| against thatportion of flap |4 -which is bounded by the base and legs of theU-shaped slit 21 will be depressed out of the plane of the flap topermit the tab 3| to pass through the slit 21. When the pressure isreleased after the outer edge or lip 32 of tab 3| has cleared the baseof slit 21, the natural resilience of the material causes theilaps toreturn to their proper positions squarely across the carton end with allof the naps securely inter-locked in the manner intended.

Under some circumstances it may be desirable to effect the ap lockingoperations simultaneously as mentioned. ln such case the side llaps arefirst folded over and across the carton end and are followed insuccession by the rear ap and then the front flap. After all of theilapsvare in their end closing positions the operator presses againstthe front flap I3 in the same manner and to substantially the sameextent (perhaps slightly more pressure is required) as that describedabove in connection with the interlocking of the front and rear flaps,whereupon all of the ilaps are bowed inwardly of the carton end and thetabs 26 caused to enter slit parts 22 and the tab 3| to enter slit 21.Release of nger pressure permits the aps to restore themselves to endclosing positions at which time they will be securely fastened togetheras shown in Fig ure 5.

The double lock thus provided is particularly effective and gives a mostsecure and strong end closure of inexpensive and simple character. It isalso of considerable significance that cartons so constructed may beset-up and closed with extreme rapidity by hand or by machine, it beinga feature of the construction of the end closure that it lends itself tomachine closing. Goods packaged in the carton, when forced against theend closure, do not cause the interlocked flaps to open but, on thecontrary, tend to cause the interlock of the aps to become tighter andless susceptible of unlocking. Many other advantages might be mentioned.

Although the invention has been illustrated and described in a singlepreferred embodiment, it is capable of considerable modification andvariation as well as of other adaptations. Consequently it is desiredthat the invention be limited only by its spirit and the scope of theappended claims.

I claim:

1. A self-locking end closure for cartons cornposed of foldable materialand having two pairs of opposed side walls forming a tubular bodycomprising, an end closure flap attached to each of the side walls atone end of the body and adapted to fold inwardly over said carton and toclose the same, each of one pair of oppositely disposed flaps having aslit including a part intersecting and extending from one of its freeside edges intermediate of the ends of such edge toward the oppositefree side edge of such nap and a part extending thence at an angle lessthan a straight angle toward but terminating short of the outer freeedge of such flap, that one of the other pair of flaps which liesadjacent to those free side edges of the first said flaps opposite tothe slit side edges of such flaps being provided with a laterallyextending locking tab at the outer end portion of each free side edgethereof, said laterally extending tabs being adapted to be sprungthrough said slits, the last said flap being arranged to overlie thesaid slit flaps and having a slit therethrough wholly within itsmarginal bounds, the remaining closure ilap being adapted to overlie thethird said flap and having a locking tab adapted to be sprung throughthe slit in the said third flap.

2. A self-locking end closure construction for cartons composed offoldable material and having two pairs of opposed side walls forming atubular body comprising, an end closure nap attached to each of the sidewalls at one end of the body and adapted -to fold inwardly over saidcarton and to close the same, each of one pair oi oppositely disposedflaps having a slit including a part intersecting and extending from afree side edge intermediate o1' the ends of the edge toward the oppositefree side edge of the iiap and a part extending thence at an angle lessthan a straight angle-to the first part toward but terminating short oi'the free outer edge of the nap, that one of the other pair of naps whichlies adjacent to those free side edges of the rst side naps opposite tothe slit side edges oi such flaps being provided with a laterallyextending locking tab at the outer end portion of each tree side edgethereof, saidv laterally extending tabs being adapted to pass throughthe rst parts of said slits, the last said tlap being arranged tooverlie the rst said pair of iiaps and having a U-shaped slittherethrough within its margins with the edges of the U directed towardthe outer edge of the flap, the remaining closure iiap being adapted tooverlie the third-mentioned flap and having a locking tab on its freeouter edge adapted to be passed through said U-shaped slit in thethird-mentioned ilap.

3. A self-locking end closure construction for cartons composed offoldable material and havF ing two pairs of' opposed side walls forminga tubular body comprising, an end closure iiap attached to each or theside walls at one end of the body and adapted to fold inwardly over saidcarton and to close the same, each of one pair of oppositely disposednaps having a slit including a part intersecting and extending from afree side edge intermediate of the ends of the edge toward the oppositefree side edge of the iiap and a part extending thence substantially ata right angle to the first part toward but terminating short of the freeouter edge of the nap, that one of the other pair of flaps which liesadjacent to said opposite free side edges of said pair of slit ilapsbeing provided with a laterally extending locking tab at the outer endportion of each free side edge thereof, said laterally extending tabsbeing adapted to pass through the first parts of said slits, the lastsaid iiap being arranged to overlie the rst said pair oi' flaps andhaving a U-shaped slit therethrough within its margins with the edge ofthe U directed t0- ward the outer edge of the flap, the remainingclosure flap being adapted to overlie the thirdmentioned ap and having alocking tab on its free outer edge adapted to be passed through saidU-shaped slit in the third-mentioned nap. l MITCHEL E. HOLY.

